Self-adjusting device for finishing tools



J ly 4, 1 1 c. POUGNAND 2,990,730

SELF-ADJUSTING DEVICE FOR FINISHING TOOLS Filed April 18, 1958 aSheets-Sheet 1 July 4, 1961 c. POUGNAND SELF-ADJUSTING DEVICE FORFINISHING TOOLS Filed April 1a, 1958 6 Sheets-Sheet 2 y 1961 c. POUGNAND2,990,730

SELF-ADJUSTING DEVICE FOR FINISHING TOOLS Filed April 18, 1958 6Sheets-Sheet 3 s {5a l l a y 1961 C.POUGNAND 2,990,730

SELF-ADJUSTING DEVICE FOR FINISHING TOOLS Filed April 18, 1958 6Sheets-Sheet .4

Fig.6.

July 4, 1961 c. POUGNAND 2,990,730

SELF-ADJUSTING DEVICE FOR FINISHING TOOLS Filed April 18, 11.958 6Sheets-Sheet 5 Fig.7.

. 2,990,730 SELF-ADJUSTING DEVICE FOR FINISHING TOOLS Filed April 18,1958 C. POUGNAND July 4, 1961 6 Sheets-Sheet 6 United States Patent Thisinvention relates in general to machine-tools and hasspecific referenceto means for automatically adjusting the position of finishing tools ontheir tool holder during the operation of the machine-tool.

Tolerances for finishing workpieces are becoming increasingly smallerand this leads tomore and more frequent re-adjustments of the toolsutilized in finishing operations to compensate tool wear.

Now it is the essential object of this invention to provide a deviceadapted, in combination with adequate measuring means checking the sizeof the workpieces during their machining, to automatically adjust one ortwo tools carried by a common spindle, in order to displace these toolsindependently of each other to an extent consistent with the prescribedmachining tolerances.

This automatic device comprises essentially a rod mounted in thespindle, responsive to a control apparatus, and adapted to perform onthe one hand axial movements in either direction from an intermediate ormiddle position in order to cause said rod to move to another or extremeposition in which it acts on a single tool holder while temporarilyreleasing said holder, and on the other hand rotational movements ofadequate magnitude and direction, whereby the rod may alter the positionof said holder, the latter being mounted with a view to reduce thedisplacements of the active or cutting portion of the tool to theminimum quantity required for effecting the necessary adjustment.

The operation of the device according to this invention is controlled bya measuring apparatus checking the dimension of the workpiece whichresults from the machining operation. When this dimension approaches oneof the tolerance limits, the control apparatus receives from themeasuring apparatus adjustment signals or data causing said controlapparatus, with the assistance of the device, to bring the toolconcerned to another position corresponding to the other limit of thetolerance.

Each too-lholder may be mounted to permit the actuation of said rod bymeans of an eccentric, cam, ramp or like member.

In order to afford a clearer understanding of this invention and of themanner in which the same may be carried out in the practice, referencewill now be made to the accompanying drawings forming part of thisspecification and illustrating diagrammatically by way of example atypical embodiment of the invention. In the drawings:

FIGURE 1 illustrates in longitudinal section a boretu-rning spindlecarrying two finishing tools or inserts and equipped withaself-adjusting device according to this invention, wherein the toolholders are actuated from the rod in two different manners, by aneccentric and by a cam, it being understood that the same arrangementmay be provided for both tools;

FIGURE 2 is a section taken upon the line II--II of FIG. 1;

. FIG URES 3 and 4 are an elevational view and a plane view respectivelyof the eccentric controlling the central tool hold 5 and 6 are viewscorresponding to FIGS. 3; and,4, respectively and showing moreparticularly the cam for. adjusting the peripheral tool holder;

FIGURE 7 is a longitudinal section illustrating an I Patented July 4,1961 ICC apparatus for controlling the device illustrated in thepreceding figures; and 1 FIGURE 8 is a section taken upon the lineVIII-VIII of FIG, 7.

Referring first to FIG. 1, the tool-holder block 1 secured on themachine spindle 2 comprises a central tool holder 3 mounted in a boreslightly eccentric relative to the axis of rotation X-X of the spindle,and a peripheral tool holder 4 mounted on a prismatic slide 5 constantlyurged by spring means 6 for engagement with a cam 8 solid with a pin 7rotatably mounted in the block 1. I

In the example illustrated the tools fitted in the tool holders 3, 4 areused for machining simultaneously the bores 50a and 50b respectively inworkpiece 50. Obviously, in certain types of works only one tool may beused instead of the two illustrated.

The eccentric portion of the central tool holder 3 comprises on theinner side of the block 1 an internallytoothed portion 3a (see FIGS. 3and 4). On the other hand, the pin 7 comprises at its inner end a pinion7a (FIGS. 5 and 6).

A central rod 9 extends through, and is coaxial to, the spindle 2, andis formed with a toothed end 9a in meshing engagement with the innerteeth 3a of the tool holder 3 and also with the pinion 7a of pin 7. Thiscorresponds to the middle position of the central rod 9. From thisposition the rod may be moved in an axial direction either towards thefront end of the spindle or backwards. The rod '9 is mounted inappropriate bearings (not shown) and the aforesaid teeth form spurgears.

The tool holder 3 is locked by two pins 10, 11 in conjunction withspring washers 12 or the like.

The slide 5 carrying the tool holder 4 is mounted for sliding movementin guideways 1413, 143a (FIG. 2), and locked against movement in theseguideways by wedge members 144, 144a engaged by tapered bearing members146, 146a carried by pins 13, 13a. These pins aresolid with push members14, 14a respectively andurged in the upward direction, as seen in FIG.2, by spring washers or like resilient members 15, 15a engaging thesepush members.

The central rod '9 carries a cylindrical block 16 solid therewith andconcentrical thereto, which is disposed between two wedge members .17,18 so as to engage one or the other of these members, according as therod is moved in one or the other axial direction. The peripheral surfaceportions of this block 16 which are to engage the relevant faces of thewedge members 17, 18 are machined to present an adequate inclinationcorresponding to that of these faces. The wedge member 17 is arranged tomove the pin 11 against the resistance of the spring washers 12. On theother hand, the wedge member 18 is arranged to move the push members 14,14a against the resistance of the spring washers 15, 15a.

With this arrangement, the position of the tool holder 3 may be adjustedby displacing the rod 9 in the direcv tion of the arrow F to the properextent.

Due to this movement, the teeth 9a of rod 9 engage more deeply theinternally-toothed portion 3a of the tool holder 3 and are thereforedisengaged from the pinion 7a of pin 7. At the same time, the block 16engages the wedge member 17 and moves the pin 11 to free the pin 10which, with the assistance of suitable spring means, releases the toolholder 3;

Then, the rod 9 is rotated through an angle corresponding for example tothe pitch of the aforesaid spur gears.

' By virtue of the eccentric arrangement explained hereabove, thedistance between the operative end of the tool and the spindle axis X--Xis altered. By properly select mg the eccentricity (shown with a greatexaggeration in the drawing in order 'rnore clearly to showthe principleTo-adjust the position of the peripheral tool holder 4,

the rod 9 is moved in the direction of the arrow F and then rotated asrequired.

During this movement, the block 16 forming an integral part of the rod 9has moved the wedge member 18 and thus the spring washers 15, 15a arecompressed through the medium of the push members 14, 14a.

The pins 13, 13a solid with these push members 14, 14a respectively willthus release the tapered bearing members 146, 146a.

Under these conditions, the slide 5 of the tool holder 4 is free fromits guideways 143, 143a and wedge members 144, 144a.

During its axial movement, the pinion 9a is disengaged from the pinion3a of tool holder 3 but is still in meshing engagement with the lateralpinion 7 a.

The rotational movement of block 16 causes the pin 7 to rotate and thecam 8 solid therewith changes in the proper direction the position ofthe slide 5 and tool holder 4.

By returning to its middle position the rod 9 permits the movement ofthe members 18, 14, 14a, 13 and 13a with the assistance of springs 15,15a in a direction opposite to that of the preceding movement. Thus, theslide 5 is re-locked automatically.

The diflerent movements of the rod are obtained with the assistance of acontrol apparatus mounted for example at the rod end opposite to the endcarrying the tool holders. This apparatus may be actuated hydraulically,pneumatically, etc.

By way of non-limiting example, FIG. 7 shows a mechanical embodiment ofthis control apparatus which is adapted to be actuated from a source ofcompressed air.

The mechanical component elements of this apparatus are housed in ahollow sleeve 19 of which one portion 19a ofthe outer surfaceconstitutes a pulley for driving the spindle 2. These component elementsare shown in the position corresponding to the middle position of therod 9.

Secured on the sleeve -19 and on the side of the headstock 20 is a hub19b keyed on the hub 2a of the tubular shaft 2. The rod 9 extends freelythrough this hub. On the other hand, a pinion 21 is keyed at 21a on thehub 19b. On the extension of rod 9, between a shoulder 9b and an endbolt 43 are mounted a pinion 22 keyed on the rod 9 by means of a key2211, a distance-piece 23 comprising an annular heel portion 24, and anend distance-piece 25. The pinion 22 has internal teeth 22b meshing withthose of pinion 21.

Coaxially to the rod 9 is a cylinder 26 bearing with its lower end (thatis, the end adjacent to the headstock 20) on the hub 19b of sleeve 19through the medium of a ball-bearing 27 wedged on this hub and held inposition by the stop washer 44. The cylinder 26 is keyed at 26a withpinion 22 so that the latter can slide axially relative to thiscylinder. At its upper end, the cylinder 26 is closed by a member 28whereby this cylinder, in conjunction with the ball-bearing 27, is heldagainst axial movement. This cylinder 26 is formed with an annularrecess 26b in which a pair of annular pistons 29, 30 held in properspaced relationship by springs 31 are adapted to slide on thedistance-piece 23. Compressed-air inlets 32 and 33 are provided forcontrolling the displacement of either of these pistons. Thus, when thepiston 30 is pushed downwards, that is, toward the headstock 20, itengages the heelportion 24'. From this moment on, it carries along thedistance-piece 23 and pinion 22, the latter slid: ing within thecylinder 26, and therefore the rod 9 proper (in the direction of thearrow F) since the pinion 22 engages the shoulder 9b of this rod. Thismovement is stopped when the heel portion 24 engages the piston 29. Atthis time, the pinion 22 is no more in meshing engage-v ment with pinion21.

The same movement but in the reverse direction (as shown by the arrow F)is obtained by actuating the other piston 29. Indeed, when compressedair is supplied through the inlet 32, the piston 29 moves upwards andcompresses the springs 31 until the piston engages the heel portion 24.From this moment on the piston carries along the distance-piece 23upwards, and through the medium of the other distance-piece 25 and ofthe end bolt 43it moves the rod 9 in the direction of the arrow F. Ineither case, when the supply of compressed air is discontinued, thesprings 31 restore the pistons 29, 30 and rod 9 to their initialpositions, respectively.

The upper end of sleeve 19 which is opposite to the headstock 20 isclosed by a member 34 and therefore constitutes a cylinder 45 in which apiston 35 constantly urged to its uppermost position by springs 36 isslidably mounted, these springs bearing with their opposite ends on amember 37 engaging a collar 19c of sleeve 19. This piston 35 is rigidwith straight splines 38 meshing with corresponding splines 37a formedon member 37, thus compelling said piston 35 to move in a directionparallel to the axis of rod 9 without revolving in relation thereto.Furthermore, this piston 35 carries helical teeth 39 in meshingengagement with corresponding helical teeth formed on the inner face ofa ratchet wheel 40 held between a pair of thrust ball-bearings 46 and47. The lower ball-bearing 46 is clamped between the member 28 andratchet wheel 40, and the upper ball-bearing 47 is disposed between thisratchet wheel 40 and a check ring 48.

Meshing with the teeth of ratchet wheel 40 is a pawl 41 (FIG. 8) pivotedin a recess formed at the upper end of member 28. The check ring 48 isassembled with member 28 and cylinder 26 by means of the same fasteningmembers, for example screws 49. The downward axial movement of piston 35(when the upper face thereof is subjected to the pressure of thecompressed air) will thus cause the ratchet wheel 40 to rotate in theclockwise direction (as seen in FIG. 8), this rotation being transmittedto member 28 and cylinder 26 through the medium of pawl 41. When theapplication of pressure to the upper face of piston 35 is discontinued,this piston is urged upwards by the return spring 36. During thismovement the ratchet wheel 40 revolves in the counter-clockwisedirection (FIG. 8) without carrying along the pawl 41 as the latterescapes the ratchet teeth in this direction.

The ratchet wheel 40 comprises as many external teeth (co-acting withthe pawl 41) as there are teeth on pinions 3a, 7a, 21 and 22. The pitchof the helical teeth 39 of piston 35 is such that each properly limitedmovement of this piston toward the headstock causes a rotation of theratchet wheel 40 and therefore of cylinder 26, pinion 22 and rod 9, thisrotation corresponding to one pitch of any one of these four pinions.

A rotary three-way distributor 42 of the type compris ing three separatepassages 42a, 42b, 420, for the compressed air is provided at the end ofthe sleeve 19 which is opposite to the headstock 20. The distribution ofcompressed air proper is controlled in turn by adequate means as willreadily occur to anybody conversant with the art.

Besides, the apparatus and instruments provided for checking the sizesof the workpieces may be of any suitable and known type, provided thatthey are capable of converting their measurements into an average valueproducing control signals or like data adapted to be fed to said controlapparatus but only when a pre-adjusted value is attained, this valuebeing approached below the. limit of the prescribed tolerance.

What I claim is:

1. A device for selectively adjusting the position of two tools mountedon two tool holders housed in a common spindle for finishing workpieces,said device comprising a member axially movable inside said spindle,means for driving said movable member in the axial direction on eitherside of a middle position to one or the other of two extreme positions,means for rotatably driving said movable member about its axis, othermeans for locking said tool holders against motion when said movablemember is in its middle position and releasing one of said tool holderswhile maintaining the other one in its :locked condition when saidmovable member is moved to one of its extreme positions, and means forproducing a small radial movement of the released tool holder when saidmovable member is in its corresponding extreme position and rotated, inorder to compensate for tool wear.

2. A device for selectively adjusting the position of two tools mountedon two tool holders housed in a common spindle for finishing workpieces,said device comprising a rod axially movable in said spindle, means fordriving said movable rod in the axial direction from a middle positionto one or the other of two extreme positions, means for rotatablydriving said movable rod about its axis, a pinion solid with said rod, afirst rotary member controlling the radial movement of a tool holder, asecond rotary member controlling the radial movement of the other toolholder, each of said first and second rotary members comprising a set ofteeth adapted to engage the teeth of said pinion when said movable rodis in its middle position, whilst only one of said sets of teeth is inmeshng engagement with said pinion when said movable rod is in one ofits extreme positions, means for locking said tool holders when saidmovable rod is in its middle position and unlocking one of said toolholders while maintaining the other tool holder in its locked conditionwhen said movable rod is brought to one of its extreme positions,whereby when said movable rod is in one of its extreme positions androtated about its axis said pinion may drive the rotary member withwhich it is in meshing engagement, said rotary member producing in turnthe radial movement of the relevant tool holder.

3. A device as set forth in claim 2, wherein said means for locking andunlocking said tool holders comprise a cylindrical block solid with saidmovable rod, and wedge members adapted to lock said tool holders intheir position of adjustment, said wedge members being disposed oneither side of the middle position of said cylindrical block and adaptedto be selectively moved by said block for unlocking the revelant toolholder when said cylindrical block is moved to one of its extremepositions.

4. A device as set forth in claim 2, wherein each of said tool holdersis eccentered relative to the rotary member on which it is mounted.

5. A device as set forth in claim 2, wherein one of said rotary memberscarries a cam, said tool holder being urged by resilient means againstsaid cam.

6. A device as set forth in claim 1, wherein said means for axially androtatably driving said movable member comprise a compressed-airdistributor, a first, a second, and a third piston adapted to be movedin the axial direction by means of said compressed air selectivelysupplied by said distributor, said first and second pistons con trollingrespectively and selectively the axial movements of said movable memberin one or the other of its extreme positions, said third pistoncontrolling the rotation of said movable member, said compressed-airdistributor being adapted to produce the rotation of said movable memberonly between two axial reciprocations of said movable member.

References Cited in the file of this patent UNITED STATES PATENTS2,267,186 Blood Dec. 23, 1941 2,270,406 'Blood Jan. 20, 1942 2,780,467Jackson Feb. 5, 1957 2,883,897 Allemann Apr. 28, 1959 FOREIGN PATENTS880,087 Germany June 18, 1953

